examples: Add assets of graphics/bgextpalette example

examples/graphics/bgextpalette/assets/convert.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+grit blue.png -ftb -fh! -gTFF00FF -gt -gB8 -mR8 -mLs
+# Only generate palette for the other two
+grit red.png -ftb -fh! -gTFF00FF -gt -gB8 -mR8 -mLs -m! -g!
+grit green.png -ftb -fh! -gTFF00FF -gt -gB8 -mR8 -mLs -m! -g!
+
+for file in *.bin; do
+    mv -- "$file" "${file%.bin}"
+done
+
+mv *.pal *.img *.map ../nitrofiles/bg
+
+grit default.png -ftb -fh! -gTFF00FF -gt -gB8 -m!
+
+for file in *.bin; do
+    mv -- "$file" "${file%.bin}"
+done
+
+for file in *.img; do
+    mv -- "$file" "${file%.img}".fnt
+done
+
+mv *.pal *.fnt ../nitrofiles/fnt